SF's Mining Exchange Building to Merge into New Shorenstein Office Tower

Developer Shorenstein Properties LLC recently selected San Francisco-based Heller Manus to design a proposed 19-story office tower at 350 Bush, site of the historic San Francisco Mining Exchange building.

The 350,000-sq.-ft. project will include an 18,000-sq.-ft. street level retail and restaurant galleria and a 175-vehicle valet parking garage.

The office tower will rise from the Mining Exchange, set back to allow the historic building to retain its distinctive presence, according to the designers. The restoration will preserve the building's exterior and interior architectural features, including the decorative ceiling details of the main trading room and the original elements of the grand lobby as well as the terra cotta façade, pediment and columns. The Mining Exchange's trading floor will become the entrance lobby for the new office building and will open at the rear into a street-level galleria with shops and restaurants functioning as a pedestrian breezeway between Bush and Pine streets.

Heller Manus said the tower's façade will be a light-colored limestone complimenting the terra cotta façade of the adjacent Russ Building. The building's design will be accented by a grey-green glass atrium and ornamental set backs with French doors that open onto balconies and terraces providing city views.

San Francisco-based Shorenstein Properties LLC (formerly Shorenstein Co.), along with its partners The Swig Co. of San Francisco and Weiler Arnow Investment Co. of New York, purchased the downtown site in the 1960s and were about to begin the development when the 2001 citywide commercial real estate depression began. However, in the past year, vacancies in the city, once in the 20 percent range, have dropped to 13 percent.

The owners hope to begin construction later this year.

The city approved the development proposal for the new office tower with a provision for additional public open space. Shorenstein agreed to expand the park area of St. Mary's Square, located diagonally from the proposed tower on Pine Street between Grant and Kearny streets. St. Mary's Square will increase by 5,127 sq. ft., extending to the corner of Kearny and Pine Streets adjacent to the rooftop penthouse of the proposed 500 Pine Street building. The park expansion will feature limestone pavers, an expansive lawn, bench seating, landscaping with bamboo, a variety of annuals and perennials, a pergola with flowering vines, and sculpture art work.

Formed in 1862 to centralize trading in mining stocks, the San Francisco Mining Exchange was the second oldest stock exchange in the nation. Trading in mining stocks waned with the decline in mining activity in the 1880s, but in the early 1920s, trading in mining stocks surged again in the general market speculation of the post-World War I era. In response to the surge in trading, the Mining Exchange hired Miller & Pflueger to design the 5,700-sq.-ft. 350 Bush Street, which opened in 1923. 350 Bush is an adaptation of the classical temple form much favored by financial institutions in the period; the building's pediment and four pairs of fluted columns recall the New York Stock Exchange, constructed 20 years earlier. The building served as a trading hall for mining commodities until 1928.

The Mining Exchange was replaced by the San Francisco Curb Exchange, which operated there until 1938. After the Curb Exchange moved, succeeding tenants were the San Francisco Chamber of Commerce (1938-1967) and Western Title Insurance (1967-1979). The building has been vacant for almost 25 years.